Hacking the planet: who decides?

Hacking the planet: who decides?

来源：未知 作者：亓右 时间：2017-12-03 03:01:08

By Jim Giles in Asilomar, California Editorial: To hack the planet, first win trust Plans are taking shape for the day when a global coalition may have to “hack the planet” in a bid to reverse the ravages of global warming. Proposals to cool the Earth by deploying sunshades or sucking carbon dioxide from the atmosphere were considered fanciful just a few years ago, but are now being considered by politicians in the US and UK. At a gathering of key scientists and policy experts held in Asilomar, California, last week, detailed debates began over who should control the development of a planetary rescue plan. The sense at the meeting was that drastic emissions cuts are the best way to limit the catastrophic droughts and sea-level rises that global warming is expected to cause. But the failure of December’s summit in Copenhagen, Denmark, and the relentless rise in global CO2 emissions have persuaded many to reluctantly consider geoengineering solutions (see diagram, right). Few argue against “artificial trees” that could suck CO2 directly from the atmosphere (see “Artificial trees on the way” in the box below). But more controversial proposals – to bounce solar energy back out into space, for instance – split the conference, with policy experts warning climate scientists that there would be a public backlash. Oliver Wingenter at the New Mexico Institute of Mining and Technology in Socorro presented details of an ambitious plan to shift westerly winds. Temperature and pressure changes over the Southern Ocean are thought to have pushed these westerlies 3 to 4 degrees south over the last 50 years. This shift strengthens the ocean currents that bring warm, salty water to the surface, where it accelerates the melting of Antarctic ice. Wingenter proposes seeding the Southern Ocean with particles of iron to boost phytoplankton growth. Plankton release a chemical called dimethyl sulphide into the atmosphere which helps cloud droplets form. More droplets mean whiter clouds that bounce more solar energy away from Earth. Wingenter calculates that it would be possible to cool regional temperatures by 0.5 ˚C, which could push the westerlies back towards their original position. Little is known about the side effects, however. Cooling a small region by 0.5 ˚C could dramatically change rain patterns. The impact of plankton blooms on ocean life is also poorly understood. Computer models can go some way to filling in these blanks, and Wingenter foresees at least 10 years of computer studies before field tests could kick off. Other solutions could be field-tested sooner, raising the delicate question of whether such experiments should be allowed in the first place, and what forms they could take. Modelling has already shown that stratospheric clouds of sulphate particles could rapidly cool the planet. David Keith of the University of Calgary, Canada, has submitted a paper to Nature in which he outlines a proposal to release about a tonne of sulphate particles from a NASA plane at an altitude of 20 kilometres. The results would help researchers refine their models, and the number of particles released would be far short of the number required to produce a significant cooling effect. Silver Lining, a non-profit organisation founded by Kelly Wanser, an entrepreneur based in San Francisco, California, has a team of 35 scientists working on a cooling process in which a flotilla of boats fire particles of sea-salt into the atmosphere, where they would whiten clouds. The group is seeking funds for pilot research involving 10 ships and 10,000 square kilometres of ocean. Kelly Wanser says it could take place in three to four years. This study would not use enough particles to create a noticeable cooling effect. Many climate scientists in Asilomar thought regulations that govern other oceanographic experiments would probably provide sufficient oversight of this project. Wanser also argued extra regulation would create potentially dangerous delays, as governments might later be forced to deploy a technology that had not been properly tested. That view split delegates at Asilomar. Social scientists and policy experts took issue with the view that trials did not need further oversight. They warned of a popular backlash unless would-be geoengineers consult with the public before running such studies. Just running tests sends a signal that scientists are interested in a future for geoengineering, says Shobita Parthasarathy at the University of Michigan, Ann Arbor. “The intention is to expand the process. The path will have been set.” If experiments progress to a larger scale, a second problem arises: which nations should decide whether a proposal has proved safe enough to implement? Most agreed that as some solutions could have a global impact, they could only be deployed after global talks, led by the United Nations, for instance. Talks would have to include plans to compensate people whose livelihoods could be damaged by side effects. Others argued that global negotiations could become impossible to manage, and cited UN-led climate talks as an example of how all-inclusive efforts can fail to solve problems requiring decisive action. Richard Benedick, president of the US National Council for Science and the Environment and a former US government negotiator, circulated a document in which he argued that the principles governing geoengineering research should be developed by a group of 14 nations, including the US, several European nations, India and China. His proposal garnered some interest, but at least one person New Scientist spoke to was disapproving. “I cannot imagine a few countries making a decision for everybody,” says Pablo Suarez, who studies climate and humanitarian disasters at Boston University. “Participation is difficult, but that is not an excuse for not doing it.” A lack of consultation could fuel campaigns against geoengineering similar to those that have derailed the use of genetically modified crops in Europe, Parthasarathy warns. Such protests seem to be taking off already. While delegates were talking in Asilomar, a body of over 70 environmental, health and social groups published an open letter attacking the meeting. “Such a discussion cannot happen without the participation of the full membership of the United Nations,” it reads. “Determining guidelines for geoengineering research and testing in the absence of that debate is premature and irresponsible.” There is one geoengineering solution that almost everyone would like to see work. If carbon dioxide can be removed from the air and stored safely underground, we might be able to stave off the worse effects of climate change. The big problem is that sucking CO2 out of the atmosphere is expensive: many estimates put the cost at close to $1000 for each tonne captured. It might, however, turn out to be a lot cheaper than that. In October 2009, David Keith, a climate and energy researcher, founded Carbon Engineering in Calgary, Alberta, Canada. The firm aims to build a device to captureCO2 at economically viable prices. He claims his device will draw down a tonne for US$100 to $250. He did not release details of the device at the Asilomar conference, but said that it involves scaling up existing processes for capturing CO2, which involve passing the gas over a substance such as sodium hydroxide. The gas combines with the chemical and can then be removed and stored underground. Keith says Bill Gates has invested in Carbon Engineering,